Chemotaxonomic and phylogenetic analyses of Sphingomonas strains isolated from ears of plants in the family Gramineae and a proposal of Sphingomonas roseoflava sp nov.

Chemotaxonomic and phylogenetic characteristics of Sphingomonas strains iso lated from plants of the family Gramineae were investigated. All strains co ntained the monosaccharide (glucuronic acid) type of glycosphingolipid (GSL -1). Most were found also to contain the oligosaccharide-type glycosphingol ipids. Fatty acid and sphingosine profiles of the isolates were identical, although the ratio of the contents varies among the isolates. They all cont ained ubiquinone Q-10, and the G+C contents were from 66 to 68%. Phylogenet ic analysis using 16S rRNA gene base sequences revealed that all the isolat es were placed in the phylogenetic group of Sphingomonas paucimobilis in th e alpha-4 subclass of Proteobacteria. By DNA-DNA hybridization experiments, the plant isolates were divided into five genotypic groups (groups 1 to 5) . The strains of group 5 showed common physiological characteristics and fo rmed pink-yellow colored colonies. Based on these results, Sphingomonas ros eoflava sp. nov. was proposed for that homology group.